Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/23/18

Area Forecast Discussion
National Weather Service Wakefield VA
1042 PM EDT Fri Jun 22 2018 .SYNOPSIS... A frontal boundary located just north of the Virginia North Carolina border early this morning, will gradually lift back north as a warm front later today into Saturday morning. A cold front will drop across the area Sunday night into Monday morning. && .NEAR TERM /THROUGH SATURDAY/... As of 1030 PM EDT Friday... Latest analysis reveals quasi-stationary boundary draped across south central VA back into W VA/S WV. Weakening upper low over the Ohio Valley continues to gradually lift ENE toward the interior northeast. Several shortwaves pinwheeled east across the northeast/Mid-Atlantic region, with convection developing largely as anticipated by the ARW and Time-Lagged HRRR this afternoon. Several strong to severe storms across central and SE VA have given way to a second round of showers producing locally heavy rainfall across the local area. Have dropped Flash Flood Watch across piedmont, with showers tapering off over western tier of the CWA. As for the overnight, potential for heavy rain continues into the early morning hours, but should diminish after 06-08z. Low clouds and patchy fog, with areas of fog west of I-95. Early morning lows in the 60s to low 70s. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... As of 345 PM EDT Friday... The frontal boundary will lift north of the area by Sat morning. The highest Pops will shift to the northern counties late tonight into Sat morning. SSW winds will pick up across the the region Sat aftn. This along with a mix of sun and clouds will push temps back into the upper 80s to lower 90s over most areas. The heat index across southeast VA and northeast NC will run around 100-102 degrees with mid to upper 90 heat indices elsewhere. A shortwave trough is progged to cross the region in the aftn/evening that could touch off a line of mainly diurnally driven tstms. A sfc trough/weak cold front will move acrs the area late Sat night thru Sun morning, with an actual cold front then dropping acrs the region Sun night into Mon morning. Have maintained chance PoPs with the trough overhead possibly kicking off scattered showers/tstms. Highs on Sun in the upper 80s to lower 90s. Monday will be dry and cooler behind the front. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... As of 340 PM EDT Friday... A ridge of high pressure builds in from the north on Tuesday as a cold front and rain exit well to the south. This will provide drier and cooler weather with afternoon highs in the low to middle 80s. Dewpoints in the lower 60s will aid in making Tuesday even more pleasant...much different than the upper 70/near 80 degree dewpoints we have been experiencing. Mid-level troughing arrives as high pressure moves offshore Wednesday, and the GFS tries to spark showers and thunderstorms over the northwest corner of our CWA in the afternoon. The EURO keeps wet weather slightly further west. Like most rain events this time of year, these appear to be diurnally driven, dissipating by late evening. Highs Wednesday will return to the upper 80s. Models diverge in solutions regarding timing/placement of rain Thursday and Friday, but expect better chances mid-morning Thursday and again Friday afternoon. Temperatures by Thursday will warm into the lower 90s and push the mid 90s by Friday. With southerly winds in play, expect muggy conditions and nighttime temperatures in the lower 70s. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... As of 800 PM EDT Friday... Am watching two areas of t-storms as of 800 PM this evening. One line extends from ~30 miles southeast of RIC to Isle of Wight County, VA. This line will likely impact PHF (and the southern edge could clip ORF). Expect gusty winds to 30-35 kt and brief IFR visibilities with this line of t-storms. Another area of showers/t-storms located from near Lynchburg south to the VA/NC border is moving NE and could possibly impact RIC between 02-05z. Accounted for this with a TEMPO group. SBY/ECG should remain dry for through at least the next few hours (less than a 30% chance of t-storms at SBY/ECG through 03z). In addition to the t-storms, IFR ceilings are being observed in RIC/SBY with MVFR conditions at PHF. Expect IFR CIGS to continue through most of the night at RIC/SBY before improving Saturday morning. CIGS could drop to IFR at PHF overnight, but not enough confidence to include in the TAF. There is a chance of some patchy MVFR fog overnight at RIC/SBY/PHF. Scattered aftn/evening showers/tstms will be possible on Saturday and Sunday. Drier conditions potentially arrive early next week. && .MARINE... As of 330 PM EDT Friday... Went ahead and extended the SCA`s for the rest of the Ches Bay (except mouth) based on latest wind gusts aoa 20 kts on back side of the frontal boundary located along the James River to ORF/VA beach. This boundary progged to meander across the waters today before lifting back north as a warm front late tonight and Sat morning. Expect diminishing winds once the onshore E-SE winds shift back to the south. This could be as early as this afternoon across the southern Ches Bay but kept the headline up through 20Z due to the uncertainty. Seas slow to respond to the onshore winds, bust expect them to reach arnd 5 ft across the northern coastal waters. Kept the SCA ending time over the coastal waters as late tonight as I expect a several hr period of seas blo 5 ft Sat morn before bumping up again later in the day. The southerly flow returns Saturday as the warm front lifts north of the waters. A Small Craft Advisory may once again be needed Sat night due to a strong SSW push and seas arnd 5 ft. && .CLIMATE... RIC received 7.39 inches of rain since midnight. This is the second all time daily rainfall record at RIC. Anotehr round of showers is expected but will need to see how much rain occurs by midnight LST (1 AM EDT). The all-time daily rainfall record at RIC is 8.79 inches set on August 12, 1955 associated with Hurricane Connie. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Coastal Flood Advisory until 3 AM EDT Saturday for MDZ021>023. NC...None. VA...Flash Flood Watch until midnight EDT tonight for VAZ064- 080>086-088>090-092-093-095>098-511>525. Coastal Flood Advisory until 3 AM EDT Saturday for VAZ075-077. MARINE...Small Craft Advisory until 4 AM EDT Saturday for ANZ650-652. && $$ SYNOPSIS...TMG NEAR TERM...MAM/JAO SHORT TERM...JDM/TMG/JAO LONG TERM...BMS/ERI AVIATION...ERI MARINE...MRD CLIMATE...
Area Forecast Discussion
National Weather Service Albany NY
922 PM EDT Fri Jun 22 2018 .SYNOPSIS... A storm system will move from the Ohio Valley tonight towards the Northeast for tomorrow, bringing on and off rain showers and isolated thunderstorms to the region, along with cloudy skies and cool temperatures. Although this storm will move out for Sunday, another cold front will keep the threat of showers and thunderstorms around, mainly for Sunday afternoon. Drier weather is expected for the start of next week, with temperatures moderating above normal through the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 920 PM EDT...Closed off upper level low is located over western Indiana and is starting to slowly shift eastward towards our area. Ahead of this feature, swirling bands of high clouds have been moving across our area. Some lower and thicker clouds are finally starting to make progress towards our area from Pennsylvania and New Jersey, as low level warm advection increases thanks to a stregthening low-level jet. CLouds look to increase and become thicker from south to north through the evening hours, but it should stay precip-free through about midnight. Afterward, hi-res model guidance (such as the 3km HRRR and NAMNest) suggest spotty areas of light rain and showers will be lifting from southwest to northeast thanks to isentropic lift in place. These showers look to be mainly from I-90 on southward, but some locations may see the ground wet by daybreak Saturday. With the clouds and showers around, temps won`t be as cool as the past few nights, with lows mainly in the mid to upper 50s. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... During the day Saturday, the upper level low will be lifting towards the Northeast. However, it will be opening up and weakening as moves within the southwest flow aft and runs into ridging in place. The surface low pressure area will also be weakening as it moves towards western New York, although a secondary area of low pressure looks to be developing across the mid-Atlantic states along the storm`s warm front. With this setup in place, our area will remain on the northerly and cooler side of the storm system, with the light low-level flow out of the east. Showers will continue to increase in coverage through the day. Although it won`t be raining the entire day, it will be on and off and models still disagree on which areas will see the highest concentration of showers. Most of the precip looks fairly light, although cannot rule out some moderate bursts from time to time. There could be a rumble of thunder, but any instability will be elevated due to the strong inversion around 850 hpa and no storms will be strong/severe. With the clouds and showers around, temps will only max out in the 60s across the region, with even some upper 50s for the Adirondacks and Greens. On Saturday night, the secondary low pressure area will be taking over as it lifts towards eastern New England. As a result, showers look to diminish in coverage, although still can`t rule one out. It will stay cloudy and damp and with the recent rainfall, there will probably be a lot of fog and low clouds remaining in place through the overnight hours with lows in the upper 50s to low 60s. On Sunday, the next system will quickly be approaching from the northwest, as another shortwave and surface cold front moves in from the Great Lakes. Another round of showers look to occur with this boundary, mainly for the afternoon and early evening hours. With some breaks of sun expected ahead of the front, there could be some surface-based instability and some thunder will be around as well, especially by late in the day, as the approaching shortwave allows for better height falls and a more favorable setup for thunderstorms. PWATs will remain fairly high, so any thunderstorm will be capable of heavy downpours, but weak lapse rates and limited 0-6 km shear should prevent any storms from getting too tall or strong. With some sunshine, highs should reach into the 70s, with even some low 80s for far southern areas. Showers and any thunderstorms will quickly diminish on Sunday evening with the passage of the cold front and it should start drying out for Sunday night. Lows will be in the 50s to low 60s with decreasing dewpoints a light northwesterly breeze. && .LONG TERM /MONDAY THROUGH FRIDAY/... The long term forecast period will begin with a low pressure system departing to our east with some lingering showers possible primarily over western New England. High pressure will build in mid week with a low pressure system approaching from the west during the mid-to- late week time period. Monday and Tuesday...As a low pressure system departs to our east and cyclonic flow overhead, there will be a slight chance for some lingering rain showers over the region with higher confidence over the New England zones. Strong upper ridging and surface high pressure will build in from the northwest on Tuesday and linger into Wednesday. Warm temps in the upper 70s to low 80s and sunny conditions will accompany the high pressure. How strong and how much blocking the aforementioned high provides will be a key player in the timing of the approaching front on Wednesday into Thursday. Wednesday through Friday...Clouds will increase on Wednesday with an approaching shortwave and associated low over the Great Lakes. The associated cold front looks to progress through the region somewhere in the late Wednesday into early Thursday time period. The timing will be crucial for thunderstorm potential and for now looks unfavorable with an overnight passage as suggested by the GFS (the ECMWF being even slower). With the low approaching and a strong high off the East Coast there will be a good pressure gradient and low level jet in place as well. This system will have to be monitored as we approach mid next week. As the system departs to our east conditions should start to dry out late Thursday or early Friday as some weak mid-level height rises push into the region. Global guidance is suggesting some Atlantic moisture advecting northward into the region with southerly flow and possibly a weak boundary moving through the region on Friday so have kept slight chance to chance PoPs in the forecast for now. The southerly/southwesterly flow will like usher in some unseasonably warm temperature into the mid to upper 80s by the end of the week. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... High pressure exiting east and a frontal system approaching from the west. Mid and high clouds are spreading northeast through tonight. The leading edge of showers will move into the KPOU area before sunrise Saturday and by mid morning at KALB, KPSF and KGFL. Including visibilities around 6SM by 07Z at KPOU and by 15Z to 18Z at KALB, KGFL and KPSF. Steadier showers could begin at KPOU by 15Z but will take until midday or early afternoon at KALB, KGFL and KPSF. Ceilings will drop to 1500 feet at KPOU and will likely stay between 2500 and 3000 feet at KALB, KGFL and KPSF. Winds will be light and variable at 6 kts or less tonight then east to southeast at 5 to 8 kts on Saturday. Outlook... Saturday Night: High Operational Impact. Likely SHRA...FG...TSRA. Sunday: High Operational Impact. Likely SHRA...TSRA. Sunday Night: Moderate Operational Impact. Chance of SHRA. Monday: Low Operational Impact. Slight Chance of SHRA. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Low Operational Impact. Slight Chance of SHRA...TSRA. && .FIRE WEATHER... Cloudy and damp conditions are expected over the weekend as an area of low pressure moves across the region for Saturday and a cold front moves through for Sunday. RH values will only fall as low as 60 to 75 percent on both Saturday and Sunday. Most of the region should see in excess of a quarter inch of rainfall, with totals generally between one half inch and one inch of rain by Sunday evening. East to southeast winds will be 5 to 10 mph on Saturday and will be switching to the west to southwest at 5 to 10 mph on Sunday. && .HYDROLOGY... No hydro problems are expected over weekend and into next week. Most of the entire Hydro Service Area /HSA/ is under abnormally dry conditions according to the latest US Drought Monitor. As a storm system moves across the region, periods of showers and a few thunderstorms are expected between late tonight and Sunday evening. Basin average rainfall amounts are expected to range between half an inch to an inch, though locally higher amounts are possible with any thunderstorms. Minimal rises are expected on the waterways. Dry weather returns Monday afternoon into the midweek before another cold front moves across the region for Wednesday into Thursday with some scattered showers or thunderstorms. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis/11 SHORT TERM...Frugis LONG TERM...Cebulko AVIATION...11/NAS FIRE WEATHER...Frugis HYDROLOGY...Frugis/Wasula
Area Forecast Discussion
National Weather Service La Crosse WI
608 PM CDT Fri Jun 22 2018 .SHORT TERM...(Tonight through Saturday) Issued at 145 PM CDT Fri Jun 22 2018 Mostly cloudy skies prevailed across the region this afternoon. Isolated showers were moving west southwestward across southern Wisconsin into east-central Iowa. A few of the showers could make it into southern portions of Grant County over the new few hours. Otherwise, skies will become partly cloudy tonight. The combination of clearing skies and light winds should allow for some patchy valley fog to form. Still some uncertainty if areas of dense fog would form due to short nights, cloud cover and light northerly winds. Evening shift will need to monitor to see if dense fog would need to be introduced to the forecast. On Saturday, partly cloudy skies should start the day with clouds on the increase later in the day. Temperatures should be a few degrees warmer than today, thus raised high temperatures a few degrees. At La Crosse, did not go quiet as warm as the latest numerical guidance which seemed a little bit too warm compared to readings across the region this afternoon. .LONG TERM...(Saturday Night through Friday) Issued at 145 PM CDT Fri Jun 22 2018 For Saturday Night into Sunday...will be watching an area of low pressure and warm front lifting northeast toward the region. Increasing warm air advection and 850mb moisture transport should generate/spread isolated to scattered showers and thunderstorms into the area. A stronger area of low pressure lifts slowly northeast toward and eventually into the area Monday night into Tuesday night for the likelihood of more showers and storms. Precipitable water values also increase into the 1.5-2 inch range, so may have to watch for some heavier rainfall with this system. This could lead to some hydrology issues with rivers running high or rivers that have ongoing minor flooding. For Wednesday through Friday...both the GFS/ECMWF build upper level ridge into the region. The ECMWF is much more amplified than the GFS. GFS also brings some convection through the ridge whereas the EC keeps things mainly dry and much warmer. Will run with a consensus at this point. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 608 PM CDT Fri Jun 22 2018 VFR conditions expected through the period as a weak area of high pressure drifts east across the region through Saturday afternoon. With the recent rains, some concern for fog development overnight, especially in the river valleys. Clearing skies and light winds through a relatively deep layer would favor fog development while the short night and both the 22.18Z NAM and 22.21Z RAP forecast soundings not showing saturation at the surface would argue against fog development. For now, have left the mention of VCFG in for KLSE while decreasing the coverage wording in the grids to just patchy with a minimal visibility restriction. && .HYDROLOGY... Issued at 145 PM CDT Fri Jun 22 2018 Area rivers are running high with some minor flooding occurring or forecast in places. Concern is increasing for more flooding heading into early next week as a couple weather systems impact the area. Vigorous system rotating through the region Monday nigh through Tuesday night looks to have the biggest impact with precipitable water values increasing into the 1.5-2 inch range. Will be keeping a close eye on the evolution of this system and potential for flooding. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...RE/DAS LONG TERM....DAS AVIATION...04 HYDROLOGY...DAS
Area Forecast Discussion
National Weather Service Wilmington NC
930 PM EDT Fri Jun 22 2018 .SYNOPSIS... Hot and humid weather with isolated thunderstorms will continue through the weekend and into Monday. Heat advisories are possible Sunday and Monday. A cold front will cross the area late Monday and Tuesday bringing a good chance for showers and thunderstorms. Much cooler weather will follow for the middle of next week before temperatures rebound above normal by next Friday. && .NEAR TERM /THROUGH SATURDAY/... As of 930 PM Friday...I`ve boosted PoPs to 30 percent from Hartsville to Bennettsville and Red Springs due to a line of thunderstorms stretching from Newberry to Saluda, SC and moving northeastward. Latest HRRR shows this area of convection surviving in at least a broken line state as it moves into this portion of the Sandhills between 11 PM and Midnight. The bulk of this activity should remain just north of the city of Florence assuming it remains on a linear trajectory. No other significant changes. Discussion from 730 PM follows... Unless an isolated shower can manage to overcome the dry air aloft across the I-95 corridor late this evening as indicated by several recent HRRR runs, the overnight period should remain dry. A modest low-level jet (20-25 kt at 925 mb) should keep surface winds from decoupling for most locations, with lows expected to remain in the very muggy 75-80 degree range. Our forecast low of 80 in Southport, should it verify, would be the second night in a row with an 80 degree low temperature there. Mercer Pier at Wrightsville Beach had an 81 degree low last night! Changes to the forecast were very minor. Discussion from 300 PM follows... 750-600 mb capping keeping a lid on deep convection so far. Along the sea breeze, and an inland thermal trough are the favored locations for an updraft to pop through but longevity would be limited. We are seeing enhanced cumulus in these regions, and the Sandhills trough appears lined up well with weak vertical circulations aloft, along a precipitable water gradient and as such a few storms could pop here. Heat Advisory posted for Williamsburg and Georgetown counties until 6 PM today, where temperatures may climb several more degrees. Saturday falls shy of heat headlines at this time, but increasing mid-level moisture and high SBCAPES should allow isolated to scattered TSTMS to develop Saturday. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 300 PM Friday...The mid level pattern will be almost due west to east for Sunday and this will lead to probably the hottest day of the year. With a deep downslope flow and a sea breeze not making much inland progress expect wide coverage of middle and upper 90s. By late Sunday night into early Monday a decent shortwave buckles the flow with a front pushing across or in the process of pushing across by the end of the period. Expect good coverage of convection with this feature as well. As for pops for Sunday, I walked back the values somewhat due to somewhat unfavorable profiles. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 300 PM Friday...One last very hot and humid day forecast for Monday but a change is coming. That change is due to a strong cold front which will drop slowly southward across the area Monday night into Tuesday, and may stall briefly before pushing further south and washing out by Wednesday. This will bring a good chance for showers and thunderstorms Monday night and Tuesday, with heavy rain possible. Although this front will dissipate into Wednesday, cool surface high pressure and broad troughing aloft will keep temps much cooler through late week before ridging develops again from the west with a possible return to significant heat by the end of the week. With the high pressure in place and cooler temperatures, convective potential will be decreased Wed-Fri, with just isolated tstms possible during the aftns. Highs Monday will climb well into the 90s with heat advisory criteria heat index values possible. Temps Tue- Thu will fall to more seasonable levels for both highs and lows before warming again to above normal at the end of the period. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Upper low will slowly move north northeast through the forecast period. Overnight, little to no fog expected the a moderate southerly wind, keeping the atmosphere fairly mixed. Saturday, convection will be hard to kick off, but it looks like a spoke of energy from the upper low will interact with the sea breeze tomorrow afternoon. Pretty strong southwest flow expected. Extended Outlook...Mostly VFR. Mainly afternoon showers and thunderstorms each day with short duration restrictions possible. A cold front will bring a better chance for showers and thunderstorms Monday. && .MARINE... NEAR TERM /THROUGH SATURDAY/... As of 930 PM Friday...The CORMP buoy a couple miles off Sunset Beach has been reporting consistent wind gusts of 20-25 knots for the past couple of hours. CCU pier observations from Myrtle Beach and North Myrtle Beach confirm 15-20 knot breezes even on the coast. I`ve updated the marine forecast to maintain these stronger wind speeds for the next several hours before winds diminish a bit overnight. The CORMP `harbor` buoy south of Southport is now reporting 3.5 foot seas as these stronger winds have had time to work on the ocean surface. Seas of 2-4 feet should continue overnight. Discussion from 730 PM follows... Seabreeze-enhanced winds gusting over 20 knots at times should diminish near shore this evening, but the synoptic wind will continue at a solid 15 knots with gusts near 20 knots all night. Seas continue to build, and should reach 3 to locally 4 feet overnight. Changes with this forecast update were very minor. Discussion from 300 PM follows... SW winds ongoing, generally 15 kt, with occasional gusts to 20 kt. Winds will pick up late Saturday a bit and an `Exercise Caution` headline may be needed beyond this period. Seas around 3 ft, but up to 4 ft outer waters at times, especially Saturday afternoon. Dominant wave energy, S waves 3 feet at 5 seconds, so bumpy conditions can be expected. Radar updates are encouraged as scattered TSTMS will prevail Saturday. SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 300 PM Friday...Fairly brisk winds across the waters through the period via good low level jetting and an approaching front very late in the period. Expect a southwest flow of 15-20 knots through the period. Significant seas should be 2-4 feet but some five footers could wander into the spectrum from time to time especially late in the period. LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 300 PM Friday...A cold front will drop slowly across the waters Monday night through Tuesday, causing winds to turn from SW early, to NE at 10-15 kts during Tuesday. This front will sag southward and then dissipate into Wednesday as high pressure elongates offshore. This drives winds to a more easterly direction on Wednesday, while maintaining those 10-15 kt speeds. Wave heights will be generally 3-4 ft through the middle of next week. However, a variety of wave groups will exist due to the fluctuating winds, so a confused spectrum is likely at times the first half of the period before an easterly 5-sec wind wave becomes dominant. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Beach Hazards Statement from 6 AM EDT Saturday through Saturday evening for SCZ054-056. NC...Beach Hazards Statement from 6 AM EDT Saturday through Saturday evening for NCZ106-108. MARINE...None. && $$ SYNOPSIS...JDW NEAR TERM...MJC/TRA SHORT TERM...SHK LONG TERM...JDW AVIATION...DL
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
856 PM CDT Fri Jun 22 2018 .UPDATE... Updated for evening discussion. && .DISCUSSION... The majority of convection has diminished across the region with the loss of heating. Went ahead and canceled the watch a little early. The HRRR is continuing to show the low level baroclinic zone retreating to the north overnight, but showing nothing more than a few showers that develop in the process. Have removed marginal severe risk over the north overnight as convective development looks to hold off until Saturday with most of it staying just north of the forecast area./26/ Prior discussion below: Through the day Saturday: Solid convective cluster has finally taken shape over the northwest portion of the forecast area in the last few hours, with this cluster advancing steadily southeast toward the heart of the region. Throughout the day convection has shown a tendency to "back-build" into an impressive nose of warmth and moisture advection aloft anchored over the Arklamiss Delta. Lately this advection feature has opened up a bit and is less focused, aiding the ability of convection to start propagating southeast. Meanwhile, the cold pool from persistent convection over northwestern zones throughout the day has generally advanced well southwest of most vigorous convection, thus ensuring the bulk of storms were "elevated" above the surface, reducing their respective potential to produce severe weather. Anyway, latest trends are increasing severe potential once again into early this evening, especially over the western two-thirds of current SVR watch # 197. The main risk through early this evening will be damaging wind gusts, although some hail (and even a stray and brief tornado) cannot be ruled out owing to seasonably impressive low level shear. The SVR watch currently is set to expire at 7 pm, but given trends it is certainly possible it may have to be extended in time a few hours, at least south of I-20. Flooding was a large concern north of I-20 over the Arklamiss Delta, but the trend toward forward-propagation (i.e., movement) is somewhat reducing the threat of at least major flooding. Thoughts are that the convective cluster should exit the region to the south/southeast by mid to late evening with a good deal of the shower and storm ending in its wake. However, latest expectations are that composite moisture convergence and advection will increase well upstream (to the west/northwest) of our region this evening in advance of another vigorous storm cluster developing toward the Red River Valley. There is some potential either this cluster, or another batch of thunderstorms induced by this cluster, will progress east/south down the re-orienting baroclinic zone and pass in the vicinity of our northern zones late tonight through tomorrow morning. A MARGINAL risk of severe thunderstorms was included in the graphics and HWO to handle this threat, but due to a high degree of uncertainty in this chaotic convective regime, there is some chance the threat will be either removed later or even upgraded. Tomorrow, by midday any storms passing through northern zones should be largely to our east or lifting to the north, leaving are region partly cloudy, seasonably breezy, and very humid. High temperatures getting into the lower 90s (and approaching the mid 90s in a spot or two) should yield heat index value near or exceeding the century mark over the majority of the area by the afternoon. Currently thinking heat advisory thresholds will not be met tomorrow so will continue to just highlight the heat stress in the graphics and HWO. /BB/ Saturday night through the work week... The story of the weekend into the work week will be that of increasing heat and humidity. The upper trough will be to our east, which will leave zonal flow and/or broad ridging across the area. With moisture left in place, this will allow for heat stress issues to begin to be a concern for much of the area on Sunday. In addition, capping should allow for a decrease in shower/storm activity. This heat concern will continue through much of the week for entire area as high pressure will expand west from the Atlantic. As heights rise, temperatures will also be increasingly warmer with some locations seeing highs in the mid 90s. This, combined with dewpoints in the mid 70s, will bring heat indices near 105 degrees. In some instances, this threshold will be exceeded. Heat advisories may be likely this week. One caveat to this may be the increased potential for diurnal showers and storms through the week. For residents planning outdoor activities, it will be wise to continue to monitor the potential for higher heat indices through the week. /28/ && .AVIATION... 00Z TAF discussion: Main concern this evening associated with scattered TSRA clusters mainly along the I-20 corridor which should diminish early this evening, but a few TSRA will continue to be possible as outflow boundary moves into the HBG/PIB area in the next couple of hours. Otherwise, expect VFR conditions until pre-dawn hours when MVFR/IFR category stratus will develop, with lowest ceilings mainly in the HBG/PIB area - expect this to gradually mix up to VFR category ceilings by late morning into early afternoon. Another disturbance could bring a few SHRA/TSRA to GLH/GWO area mid/late Saturday morning. /EC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 70 93 74 93 / 13 9 3 7 Meridian 72 95 74 94 / 22 9 3 7 Vicksburg 70 93 74 93 / 6 8 3 8 Hattiesburg 74 94 74 93 / 16 10 3 11 Natchez 75 92 74 92 / 8 10 5 10 Greenville 70 92 75 92 / 8 27 6 5 Greenwood 72 92 74 91 / 10 23 6 7 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$
Area Forecast Discussion
National Weather Service Little Rock AR
901 PM CDT Fri Jun 22 2018 .UPDATE... Continuing to monitor development of a linear convective complex, extending from south central Kansas, to the Texas panhandle. Some overall weakening of this activity is still expected as it approaches western sections of the forecast area. Have made minor adjustments to near term forecasts to refine temporal resolution of pop/wx forecasts. 55 && .PREV DISCUSSION...(ISSUED 627 PM CDT Fri Jun 22 2018) AVIATION... Forecasts will reflect expected evolution of MCS activity, most likely to affect western sections between 06 and 10z. 55 PREV DISCUSSION...(ISSUED 259 PM CDT Fri Jun 22 2018) SHORT TERM...Tonight Through Sunday Model discrepancies continue to exist with the storm system set to move into western Arkansas during the overnight and early morning hours tonight. For the past few days models have been bringing the system into northern Arkansas late Friday night and the coarser models continue to do so today. However the HRRR has consistently showed the precipitation weakening across northwest Arkansas and trending further south...similar to the location where storms are currently ongoing. If I was confident the HRRR would pan out, I could see issuing a flash flood watch across the locations in southern Arkansas where they have seen flooding today. However, will hold off on issuing a flash flood watch at this time. Stalled front over Arkansas will begin to pivot and lift back to the north on Sunday. This will keep rain chances across the northern third of the state. By late Sunday night the front will lift north into southern Missouri and bring dry weather to the state Sunday night and into Monday. LONG TERM...Sunday Night Through Thursday To begin the period, large upper troughing across the Central/Northern Plains will begin ejecting to the northeast. While shortwave trough energy associated with this feature will graze far northeastern AR, subsidence from a building upper ridge to our south should keep precip east of the area where better upper level support will exist. Significant upper ridging across the SW CONUS will spread east with time, with the center of the ridge effectively atop AR by late week into next weekend. Strong subsidence will largely prevent thunder, although isolated diurnal convection cannot be entirely ruled out. Expect hot temps to continue, with highs ranging from the low 90s north to mid/upper 90s south. Lows each night will remain in the low to mid 70s. && .LZK Watches/Warnings/Advisories...NONE. && $$ Aviation...99
Area Forecast Discussion
National Weather Service Blacksburg VA
1035 PM EDT Fri Jun 22 2018 .SYNOPSIS... A frontal boundary will drift slowly north tonight as a wave of low pressure along it moves east. Scattered to numerous showers and thunderstorms are expected across the region into tonight. The rain may be heavy at times. Low pressure will move from the Ohio Valley to the eastern Great Lakes Saturday, then eastward across New England Sunday. && .NEAR TERM /THROUGH SATURDAY/... As of 1013 PM EDT Friday... Flash flood watch for the piedmont cancelled early as heavy rain and flood threat has ended for the night. Atmosphere has been worked over but still some upper support to our west, where upper low exists over the Ohio Valley. Enough pockets of instability and deep moisture convergence to not allow for a completely dry forecast overnight but coverage of showers should be more isolated and not as strong in terms of storms and heavy rain. Pockets of fog will also form but stratus and mid level clouds may keep fog limited in coverage. Previous discussion from early evening... Forcing continues for deep convection from the Alleghanys east into the piedmont of VA along frontal boundary. Effective shear is 40-45kts across the VA piedmont with 0-1km helicity around 150 m2/s2. As we head into the evening, expect some decrease in intensity to the storms, but another hour or two of a threat for damaging winds, and isolated spinups, though so far we have not confirmed any tornado touchdowns. Will keep the flash flood watch as is, but storms have moved enough to keep flooding to minimum except minor urban flooding in Lynchburg. Previous discussion from early afternoon... Flash Flood Watch remain in effect until midnight for VAZ046-047-058-059. A closed upper low over Indiana this afternoon will open up and northeast tonight into Saturday. Numerous showers and thunderstorms have developed this afternoon in the unstable air across our region. SPC Mesoscale analysis at 18z showed Surface based CAPES from 1k to 2500 j/kg and LIs from minus 2 to minus 4 across our forecast area. The Effective bulk wind shear still demonstrates a pocket of 30 to 40 knot this afternoon. SPC in the Day One Convective outlook continued a slight risk of severe weather in our northeastern portion of the forecast area with marginal risk elsewhere. There remains a potential for supercells. Damaging winds, heavy rains and hail are the primary threat with deeper convection. Showers and thunderstorms will move east across our area this afternoon into tonight. HiResW-arw-east and HRRR capture the main band of convection quite well for this afternoon. The NAM,GFS and ECMWF showed scattered storms moving east across the region tonight. Spokes of energy associated with the upper low may result in lingering showers overnight especially in the west. Areas of low clouds and fog will develop overnight especially where heavier rain falls this afternoon. Low temperatures tonight will range from the upper 50s in the mountains to around 70 degrees in the piedmont. With the movement of the low pressure center northeast, the warm front will continue to advance north Saturday with the cold front pushing east. The cold front should move across our area Saturday afternoon into Saturday night. Shortwaves rotating around the upper trough will enhance convection. The Latest day 2 convective outlook placed a marginal chance to our east and to our west. In any case, expected scattered showers and thunderstorms again on Saturday. High temperatures will vary from around 70 degrees in the northwest mountains to near 90 degrees in the piedmont. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 253 PM EDT Friday... 500MB heights rising Saturday night through Monday night. Flow is zonal Saturday night and Sunday with more ridging by Monday. A 60 knot jet streak over the West Virginia and Pennsylvania Sunday will provide some shear and upper diffluence during the afternoon and evening. Downsloping winds and 850MB temperatures across southern Virginia and northern North Carolina will result in above normal temperatures east of the Blue Ridge on Sunday. Will stay on the warm side of guidance for maximum temperatures. Confidence for all elements is average. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 253 PM EDT Friday... Upper ridge over the forecast area on Tuesday. Northern jet stream remains progressive and models in decent agreement bringing the next trough through the northeast United States on Wednesday and Thursday. Surface high pressure over the northeast and Mid Atlantic on Tuesday will move offshore by Wednesday. This will mean a return of moisture and a daily thunderstorm threat each afternoon and evening. Potential for west to northwest surface to 850MB winds on Thursday and Friday as seen on the ECMWF may limit areal coverage of precipitation. Temperatures will be slightly above normal through the period. Confidence for all elements is average Tuesday and Wednesday and below average for Thursday and Friday probability of precipitation. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... As of 715 PM EDT Friday... Expect showers/storms to impact LWB/ROA/LYH early thru about 1z, maybe 2z LYH, the isolated threat overnight, with moisture laden airmass leading to fog and low cig potential. Will be going with at least MVFR vsbys at all sites, with lower vsbys across the mountain taf sites. Confidence is medium on this as some mid and higher level clouds and mixing may keep fog patchy/intermittent. Will see the low stratus/fog erode by 12-14z, then VFR through Sat afternoon. Storms fire up again in the afternoon, with best chance over the mountains, so have VCTS there after 18z. .Extended Aviation Discussion... A cold front will finally sweep through the region Sunday with improving conditions Monday and Tuesday. Isolated to scattered MVFR showers and thunderstorms are possible Wednesday. && .EQUIPMENT... As of 200 PM EDT Friday... The NOAA weather radio transmitter in Hinton, West Virginia that is WXM72 and broadcasting at a frequency of 162.425 MHz is off the air. Parts are on order to repair the transmitter, but there is no known time of restoration. We apologize for any inconvenience. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK NEAR TERM...KK/WP SHORT TERM...AMS LONG TERM...AMS AVIATION...KK/PM/WP EQUIPMENT...